For the extraction of vegetable oils from natural starting materials, apparatus has been provided in the past for the mechanical pressing of the oil from the raw substances. Processes are also known which involve solvent extraction where the vegetable matter is macerated in a solvent. One advantage of a solvent extraction process is that high oil yields are obtainable and denaturing of any protein in the product can largely be avoided. The invention is concerned with such extraction processes.
In conventional extraction apparatus for the purposes described, solids in the product withdrawn from the extractor and the oil to be recovered can form an intermediate product, i.e. a so-called miscella phase which must be specially treated to remove the solvent therefrom so that as little residue as possible remains in the end product of the solvent extraction.
Conventional apparatus for this purpose have unusually complex constructions, and require a number of individual components and numerous connecting ducts. In practice, moreover, these ducts can have numerous flanges for joining them together and to the other pieces of the apparatus. Because of the complexity, the cost for assembling the apparatus is excessive and because of the large number of pipe connections and the like, significant solvent losses cannot be prevented.